The use of rubbery adhesive cements for the bonding of rubber surfaces are well known, particularly in the fields of tire manufacturing and tire retreading. It is a common method in tire manufacturing, to apply an unvulcanized tread to a tire carcass by means of coating the bias cut tread ends with a rubbery adhesive cement and mating those ends. In tire retreading operations, either unvulcanized or vulcanized treads or tread-forming strips are applied to used tire carcasses which have been prepared by buffing off the old tread and coating it with a rubbery adhesive cement. Other areas of use are the manufacturing of rubber goods including, but not limited to, airsprings, conveyor belts, power transmission belts, hose, fuel cells, shoe products, rubberized roofing and dunnage bags.
When used in rubber bonding applications, rubbery adhesive cements should provide: (1) good green tack, (2) good green strength, and (3) compound compatibility. Green tack is a measure of the ability of the two mating surfaces to grab quickly and hold together while the item is being built. Given strength is a measure of the ability of the spliced surfaces to remain bonded throughout the aging period prior to vulcanization. Compatibility with the rubber compound provides an adhesive layer interface which exhibits a similar vulcanization rate as the rubber compound. This allows the interface to reach the same state of vulcanization and to exhibit similar dynamic properties, thus reducing the possibility of an opening occurring at the splice. Compatibility is measured by the hot vulcanized adhesion test, described infra.
As tread stock compositions change, there arises a need for new and different adhesive cements.